Communication over wide area networks (WANs) such as over the well-known Internet network has become more practical and useful as various technologies used in such as teleconferencing have been refined. For example, video teleconferencing has been markedly improved over the last few years. Improvements to video cameras, equipment, and videoconferencing software have allowed for cleaner and more fluid video motion, clearer audio, and sharper imaging. In many cases, improvements in video codec methods, data compression techniques, and bandwidth reservation schemes have been largely responsible for the improved quality. However, better hardware including cameras and the like have also lent to better quality.
In a typical videoconferencing session two or more users having a network-capable appliance such as a PC, a video camera and the appropriate software are connected to each other over a network such that each user may interact with a video/audio representation of all other users participating in a given session. Such users are typically represented in framed viewing widows that appear on participant's respective display monitors. Such monitors may be CRT monitors, flat panel displays, or other adapted viewer interfaces.
In a most basic application, a user may view and hear only another user to whom he has an open channel. To conference in a third party, a second channel must be opened and the first channel put on hold. In some enhanced applications, there may be several users taking part in one session. Any one of the several users may, if enabled by software and suitable hardware, view all the other participating users simultaneously in separate framed windows on his or her display during a session. A limit or capacity relating to the possible number of participating parties is generally imposed on any one active session. That number depends of the complexity level of software and hardware mix maintained on the network appliance used in the session.
A problem with prior art videoconferencing systems is that only one camera is typically provided and mounted in one position and directed to each participating user. Therefore, a user must be looking into the camera in order for a correspondent to see the user face-on. If a user's gaze is directed away from the camera, a somewhat awkward feeling can be experienced by correspondents that are conferencing with the user. This awkward feeling has to do with a state that you are talking with someone that is not meeting your gaze. In other words, a user appears on-screen to be lost or to have a lost look. This problem is routinely avoided in the television industry by prompting a person to look only at a camera that is on and actively recording. It is generally accepted that if he or she cannot do this and one camera catches them gazing into another camera, then the effectiveness of their presentation or message may be reduced.
While this problem relates to a somewhat instinctive human discomfort and may be rationalized away by practitioners of videoconferencing systems, it is nonetheless desired that improvements be made to correct the problem by providing a videoconferencing system wherein all participants appear focused and engaged (not looking off to the side).
The cause of the lost look effect is brought about by a user who instead of looking directly at a camera while talking, wants to see the person or persons he is talking to. He does this by moving his gaze from the camera to a framed window on his display containing a representation of one of the correspondents. If there is more than one window containing representations of correspondents, a user may switch his gaze from one to another while talking with them and not look at the camera at all. The resulting lost look can have a subtle affect on the seriousness of a user's message.
Some companies have attempted to reduce the problem by integrating the camera into a user's monitor or display screen. A camera placed in the center of the monitor, for example, may reduce the lateral distance from the camera to any framed windows. This can reduce the lost look effect but does not eliminate it. Moreover, if the monitor is very large and the corresponding windows are on the peripheral of such a monitor, the lost look effect may still be quite significant.
Another attempt to minimize the lost look effect has been offered by companies that provide a special screen much like a projection screen wherein a camera is mirrored into the screen. Light sensitivity is a drawback to this type of system requiring components to be held small and enclosed. Also, the screen is considerably larger than a standard PC monitor. Therefore, if the correspondent windows are on the peripheral of the screen, a lost look effect is still produced.
Other developers have attempted to use two cameras and stereo software to position a camera virtually within a display monitor screen. U.S. Pat. No. 5,886,735 was issued on such a system and is provided in an IDS filed in association with this patent application. There are still some problems even with this development.
What is clearly needed is a method and apparatus that will create a virtual camera effect that may be placed anywhere in a videoconference screen. Such a virtual camera may be trained to follow a user's angle of gaze into his screen when the user is not looking into an actual camera such that a face-on image stream representing the user may be created and transmitted to correspondents instead of an angled shot depicting a lost look.